A battery module technology for housing, in a case, an assembled battery including a plurality of battery cells has been disclosed. In particular, in a battery module including an assembled battery used in the outer space, it is necessary to establish a special mounting method depending on a required machine environment condition.
To perform power line connection in a battery module, that is, to connect the battery module to a load, a round connector disclosed in Non Patent Literature 1 has been used. In the connection of the battery module to the load, necessary specifications are determined according to a required machine environment condition. A round connector adapted to the specifications is ordered. The necessary specifications include various requests such as assembling workability and prevention of misconnection. However, concerning a connector used for power line connection in a lithium ion battery used in the outer space, there are requirements such as various tests. For many connectors, a time required from order to delivery is one year or more. A very long time is required for the delivery of the connectors. Moreover, the connectors are expensive.